During all of the various types of pulp processing, a persistently continuous and proportional admixture of processing agents to the pulp is of decisive importance in order to obtain an acceptable result.
In previously known devices the processing agent is admixed to the pulp in the lower portion of a pulp bin. The mixing device generally comprises a propeller, which accelerates the pulp to a high rate through a nozzle, whereby the surrounding pulp is continuously sucked in. The processing agent is thereby added to the pulp before it is sucked into the mixing device. In these cases, however, a high pulp concentration in the bin, for example 12%, creates a problem for achieving continuous admixing. In order to reduce this problem, bins have been designed in order to have a bottom zone of reduced size. This, however, results in a decrease in processing volume, as well as a more complicated and more expensive bin design. Such an arrangement also requires more energy, since it is an incomplete admixing technique.
According to the present invention, the above problem is eliminated in view of the fact that the processing agent is added and distributed centrally, and the pulp flow is improved. The mixing result is improved, while at the same time the energy consumption is minimized.